1. Field of the Invention
The present invention relates to a road traffic information system using an ad-hoc network, and more particularly to an apparatus and method for providing an ad-hoc network between vehicles and roadside devices and collecting/providing road traffic information using the ad-hoc network.
2. Description of the Related Art
A Dedicated Short Range Communication (DSRC) system has been widely used as a conventional road traffic information system. The DSRC system performs wireless communication between an On Board Equipment (OBE) of a vehicle and a Road Side Equipment (RSE). The DSRC system can perform wireless communication between the OBE and the RSE when, for example, a vehicle equipped with the OBE travels through a prescribed communication area formed by an antenna connected to the RSE. Preferably, the RSE may be either a small-sized mobile communication base station installed on a roadside or a road or a Wireless Local Area Network (WLAN) Access Point (AP).
FIG. 1 shows a conventional road traffic information system using such a DSRC system. When a plurality of vehicles 10, 11, 12, 16 and 19 travel through a prescribed communication area of the RSE 25, wireless communication is established between the vehicles and the RSE 25 as shown in FIG. 1. When vehicles 11, 12, 13, 14 and 15 travel through a prescribed communication area of the RSE 20, wireless communication is also established between the vehicles 11 to 15 and the RSE 20. When vehicles 17, 18 and 19 travel through a prescribed communication area of the RSE 30, wireless communication is also established between the vehicles 17 to 19 and the RSE 30. The RSEs 20, 25 and 30 receive road traffic information from a traffic information service center, and transmit the road traffic information to vehicles located within individual communication areas of the RSEs.
The road traffic information is received from a plurality of detectors mounted to a roadside or a road. The detectors may be added to the RSEs 20, 25, and 30 respectively, or may be installed independent of the RSEs. Otherwise, the RSEs 20, 25, and 30 may request driving information from vehicles 10-19 traveling along the communication areas, and may receive the driving information from the vehicles 10-19, such that the received driving information can be adapted as road traffic information.
However, the aforementioned conventional road traffic information system must add a detector to a RSE or must install a detector on the road, resulting in a complicated RSE and an increased production cost. Further, the conventional road traffic information system has a disadvantage in that it increases the amount of network load due to the increased amount of traffic between the RSE and the vehicle when the RSE requests driving information from vehicles. What is needed is an improved system and method for effectively collecting road traffic information without increasing the amount of network load and at the same time using an additional device.